All other primitive values and all native ECMAScript objects are truthy.

The production LogicalANDExpression : LogicalANDExpression && BitwiseORExpression is evaluated as follows:

Let lref be the result of evaluating LogicalANDExpression.

Let lval be GetValue(lref).

If ToBoolean(lval) is false, return lval.

Let rref be the result of evaluating BitwiseORExpression.

Return GetValue(rref).

Converting to String

With the + operator, when either operand is a string, concatenation is performed.

All native objects have a toString method. Number.prototype.toString(base) is special in that it takes a base parameter.

15..toString(16)

String(15);// Calls ToPrimitive(input argument, hint String).

Conversion to Primitive

Mathematical unary and binary operators, as well as boolean operators require the operands to be converted to primitives.

The Addition operator is used, the operands must be converted into primitive values. First, the interpreter calls the object's valueOf. If the result is a primitive value, then that value is used. Example:

var ob ={
valueOf :function(){return1;}};
ob +1;// 2.

Otherwise, if o.valueOf results in an object —and Object.prototype.valueOf does — the object's toString is called.

parseInt(s, radix)

To force use of a particular base, use the radix parameter:

parseInt("09", base)// base from 2 to 36.

If radix is omitted, the base is determined by the contents of the string. Any string beginning with 0x or 0X represents a hexadecimal number. A string beginning with a leading 0 may, in older implementations, be parsed as octal (as if raxix were 8), in ECMA-262 Ed 3 (octal digits are 0-7). If string 09 is converted to 0.

var t ="0xf";Number(t);// 15+t;// 15

Primitive to Object with Property Accessors . and []

Property access operation on string, number, and boolean primitives results in the creation of a 'temporary object, for the algorithm.